Datasheet VSC7923X, VSC7923KFL, VSC7923KF, VSC7923CA Datasheet (VITESSE)

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7923

SONET/SDH 2.5Gb/s Laser Diode Driver

Features Applications

• Rise Times Less Than 100ps

• High Speed Operation (Up to 2.4Gb/s NRZ Data)

• Single-Ended or Differential Input Operation

• Single Power Supply

• Direct Access to Modulation and Bias FETs

• Data Density Monitors

• SONET/SD H at 622Mb/ s, 1.244Gb/s,

2.488Gb/s, 3.125Gb/s

• Full-Speed Fibre Channel (1.062Gb/s)

General Description

The VSC7923 is a single 5V supply, 2.4 Gb/s laser diode driver with direct access to the laser modulation and
bias FET’s. Laser bias and modulation currents are set by external com ponents allowing precision monitoring
and setting of the current levels. Data inputs accept ECL levels. Data density outputs are provided to allow the
user to adjust the laser bias in high unbalanced data applications.

VSC7923 Block Diagram

NIOUTIOUT

DIN

VREF

VIP

VIB

MK

NMK

MIP

IBIAS

IMOD

MIB

G52203-0, Rev 3.0 Page 1
05/11/01

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

Table 1: Signal Pin Reference

Signal Type Level # Pins Description

DIN In ECL 1 Data Input
MK, NMK Out ECL 2 Data Density Differential Outputs
NIOUT Out 1 Laser Modulation Current Output (Complementary)
IOUT Out 1 Laser Modulation Current Output (To Laser Cathode))
VSS Pwr Pwr 5 Negative Voltage Rail
GND Pwr Pwr 9 Positive Voltage Rail
VIP In DC 1 Modulation Gate Node
MIP In DC 1 Modulation Source Node
VIB In DC 1 Bias Gate Node
MIB In DC 1 Bias Source Node
VREF In DC 1 Data Input Reference
T otal Pin s 24

Table 2: Absolute Maximum Ratings

Symbol Rating Limit

V

SS

T

J

T

STG

Negative Power Supply Voltage VCC to -6.0V
Maximum Junction Temperature -55°C to + 125°C
Storage Temperature -65°C to +150°C

VSC7923

Table 3: Recommended Operating Conditions

Symbol Parameter Min Typ Max Units Conditions

GND Positive Voltage Rail — 0 — V
VSS Negative Voltage Rail -5.5 -5.2 -4.9 V
T

Cl

T

J

NOTES: (1) Lower limit of specification is ambient temperature and upper limit is case temperature. (2) See section “Calculation of the

Operational Temperature
Junction Temperature ——125 °C

Maximum Case Temperature” for detailed maximum temperature calculations.

(1)

-40 — 85

(2)

°C Power dissipation = 1. 25W

Table 4: ECL Input and Outputs

Symbol Parameter Min Typ Max Units Conditions

V

IN

V

OH

V

OL

Page 2 G52203-0, Rev 3.0

Input Voltage Swing 300 — 800 mV Peak-to-peak, V
ECL Output High Voltage -1200 ——mV 50Ω to -2.0V
ECL Output Low Voltage ——-1600 mV 50Ω to -2.0V

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

REF

= -2.0V

05/11/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7923

SONET/SDH 2.5Gb/s Laser Diode Driver

Table 5: Power Diss ipat ion

Symbol Parameter Min Typ Max Units Conditions

I

VSS

P

D

P

DMAX

Power Supply Current (VSS) ——220 mA VSS = -5.5V, I

= -5.5V, I

V

T otal Po wer Di ssi patio n ——1210 mW

Maximum Power Dissipation ——1815 mW

R
V

I

BIAS

SS
LOAD

SS

= -5.5V, I

= 50mA, I

= 25Ω to GND

T able 6: Laser Driver DC Electrical Specifications

Symbol Parameter Min Typ Max Units Conditions

I

BIAS

I

MOD

V

V

V

IB

IP

OCM

Programmable Laser Bias Current 2 — 50 mA —
Programmable Modulation Current 2 — 60 mA

V

+

Laser Bias Control Voltage ——

Laser Modulation Control Voltage ——

Output Voltage Compliance

GND -

2.2V

——VV

SS

2.1

V

+

SS

2.1

—

VI

VI

BIAS

MOD

SS

= 50mA

= 60mA

= -5.2V

MOD

MOD

MOD

OUT

= I

BIAS

= I

BIAS

= 60mA,

= 0V

= 0mA

= 0mA,

T able 7: Laser Driver AC Electrical Specifications

Symbol Parameter Min Typ Max Units Conditions

25Ω load, 20%-80%,

tR, t

F

Output Rise and Fall Times ——100 ps

15mA < I

= 20mA

I

BIAS

MOD

< 60mA,

Table 8: Package Thermal Specifications

Symbol Parameter Min Typ Max Units Conditions

θ

JCC

θ

JCMG

Thermal Resistance from Junction-to-Case — 25 — °C/W Ceramic Package
Thermal Resistance from Junction-to-Case — 32 — °C/W Metal Glass Package

G52203-0, Rev 3.0 Page 3
05/11/01

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

VSC7923

Calculation of the Maximum Case Temperature

The VSC7923 is designed to operate with a maximum junction temperature of 125°C. The rise from the case to
junction is determined by the power dissipation of the device. The power dissipation is determined by the V
current plus the operating I

The power of the chip is determined by the following formula:

P

=(-VSS * ISS) + ((V

D

For example with:
V

SS

I

MOD

I

BIAS

V

IBIAS

V

IOUT

P

D

PD = 1144mW + 128mW + 64mW = 1.336W

MOD

and I

BIAS

currents.

– VSS) * I

IOUT

MOD

) + ((V

IBIAS

– VSS) * I

BIAS

= -5.2V
= 40mA
= 20mA
= -2.0V
= -2.0V

= 5.2 * 220mA) + ((5.2 - 2.0) * 40mA) + ((5.2-- 2.0) * 20mA)

)

SS

θ

The thermal rise from ju nctio n to case is

* PD. For the metal glass package, θJC = 32 °C/W. Thus the th er-

JC

mal rise is:

32°C/W * 1.336W = 42.7°C

The maximum case temperature is:

125°C – 42.7°C = 82.3°C

The absolute maximum power dissipation of the device is at:

V

SS

I

MOD

I

BIAS

V

IBIAS

V

IOUT

=-5.5V
=60mA
=50mA
=0V
=0V

= (5.5 * 220mA) + (5.5 * 60mA) + (5.5mA * 50mA)

P

D

= 1.815W

P

D

This will net a maximum junction to case thermal rise of: 1.815W * 32°C/W = 58°C

This situation will allow maximum case temperature of: 125°C – 58°C = 67°C

Page 4 G52203-0, Rev 3.0

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

05/11/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7923

Input Termination Schemes

OV (GND)

1400 1400

X

DIN

VREF

X

4300 4300

-5.2V (VSS)

SONET/SDH 2.5Gb/s Laser Diode Driver

Figure 1: Input Structure

+

-

• Nominal VREF = -1.3V

• 1400, 4300 Ohm Resistor

on die, nominal values

Figure 2: Single Ended AC Coupled

GND

SOURCE

SOURCE

50 Ohms

GND GND

Figure 3: Differential AC Coupled

GNDGND

GND

GND

-2V

-2V

50Ω

50Ω

-2V

50Ω

0.1µF

0.1µF

0.1µF

GND

VREF

0.1µF

DIN

X

X

VREF

DIN

X
X

+

-

VSS

GND

+

-

VSS

G52203-0, Rev 3.0 Page 5
05/11/01

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

Figure 4: Differential DC Coupled

SOURCE

GND

Figure 5: Single Ended AC Coupled with Offset Adjust

GNDGND

GND

-2V

50Ω

-2V

50Ω

DIN

X

X

VREF

VSC7923

GND

+

-

VSS

SOURCE

GND

GND

VSS

GND

2000

4300

GND

50Ω

.01µF

GND

DIN

X

VREF

X

.01µF

GND

+

-

VSS

Page 6 G52203-0, Rev 3.0

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

05/11/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7923

SONET/SDH 2.5Gb/s Laser Diode Driver

Figure 6: Control Signals VIP and VIB

I (MIB)

50 mA

VIB

1.5V (Typical)

2.1V (Maximum)

Typical Bias Current v.s. Bias Voltage

I (MIP)

60 mA

VIP

1.5V (Typical)

2.1V (Maximum)

Typical Modulation Current v.s. Modulation Voltage

Figure 7: Simplified Output Structure

NIOUT IOUT

XXX

OUTPUT

IP

X

I

MOD

DIFF
PAIR

I

BIAS

X

VIB

X

MIP

G52203-0, Rev 3.0 Page 7
05/11/01

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

MIB

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

Figure 8: Pad Assignments for VSC7923 Die

50µm

PAD 34 PAD 33 PAD 32 PAD 31 PAD 30 PAD 29 PAD 28 PAD 27 PAD 26

120

VREF VSS VSS VSS VSS VIP MIP MIP MIB

120µm

150µm

30µm

PAD 1
DIN

PAD 2
VSS

PAD 3
DIN

PAD 4
GND

PAD 5
GND

PAD 6
GND

1720µm

1620µm

PAD 25

VIB

PAD 24

GND0

PAD 23

OUT

PAD 22

OUT

PAD 21

GND0

PAD 20

NOUT

50µm

VSC7923

50µm

1620µm

1720µm

PAD 7
VSS

PAD 8
VSS

N/C N/C GND GND GND GND GND NMARK MARK

PAD 9 PAD 10 PAD 11 PAD 12 PAD 13 PAD 14 PAD 15 PAD 16 PAD 17

NOTES:

1) Die size = 1620µm x 1620µm

2) Actual die size = 1720µm x 17 20µm (after die are cut up)

3) Pad size = 120µm x 120µm

4) Pad pitch = 150µm

5) Space betwen pads = 30µm

PAD 19

VSS

PAD 18

VSS

50µm

Page 8 G52203-0, Rev 3.0

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

05/11/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7923

Pin Diagram for 24 Pin Metal-Glass Package

VREF

VSS

VSS

VIP

24 23 22 21 20 19

VSS

DIN
GND
GND
GND

VSS

1
2
3
4
5
6

Top

View

(LID)

SONET/SDH 2.5Gb/s Laser Diode Driver

MIP

MIB

18
17
16
15
14
13

VIB
GND
IOUT
GND
NIOUT
VSS

7 8 9 10 11 12

MK

N/C

GND

GND

GND

Note: Package bottom plate is connected to GND within the package.

Package lid is electrically unconnected.

MK

G52203-0, Rev 3.0 Page 9
05/11/01

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

Package Information - 24 Pin Metal-Glass Package

Top View

(A) MAX

Pin 1

VSC7923

Key mm In

A7.11 0.280

B6.10 0.240
C1.02 0.040

D0.76 0.030

E0.30 0.012

F2.08 0.082
G1.02 0.040
H9.52 0.375

I0.130.005

(D) TYP

(G)

(LID)

Package Lid

Side View

Package Top

(B)

(H)

NOTES:

(E) ± .002

(F)

(I)

(C)

Drawing not to scale.
Package #: 101-291-8 Issue #:1
Lid #: 101-292-3 Issue #:1

MAX

Page 10 G52203-0, Rev 3.0

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

05/11/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7923

Pin Diagram for 24 Pin Ceramic Package

VREF

VSS

VSS

VSS

DIN

GND

GND

GND

24 23 22 21 20 19

1

2

3

4

5

SONET/SDH 2.5Gb/s Laser Diode Driver

VIP

MIP

MIB

18

17

16

15

14

VIB

GND

IOUT

GND

NIOUT

VSS

6

78910

N/C

GND

GND

GND

Note: Package bottom plate is connected to GND within the package.

Package lid is electrically unconnected.

11 12

NMK

13

MK

VSS

G52203-0, Rev 3.0 Page 11
05/11/01

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

Package Information - 24 Pin Ceramic Package

Top View

A

24 23 22 21 20 19

INDEX

1

2

3

A

4

5

VSC7923

Key mm In

A 9.5 0.374

B 7.7 0.303

C 2.0 0.079
D1.27 0.050

E0.30 0.012

E

18

17

16

15

14

F 1.7 0.067
G 0.6 0.024
H11.5 0.453

I 0.125 0.005
J8.510.335

6

78910

D

11 12

13

Side View

B

F

I

G

J

H

NOTES:

Drawing not to scale.
Package #: 101-312-0 Issue #:1

L id #: 101-303-1 Issue #:1

C

Page 12 G52203-0, Rev 3.0

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

05/11/01

Preliminary Data Sheet

VITESSE

SEMICONDUCTOR CORPORATION

VSC7923

SONET/SDH 2.5Gb/s Laser Diode Driver

Ordering Informatio n

The order number for this product is formed by a combination of the device number, and package style.

VSC7923

Device Type

2.5Gb/s Laser Diode Driver

XX

Package Style (24 pin)

CA: Metal Glass Package—Straight Lea ds
KF: Ceramic Package—Straight Leads
KFL: Ceramic Package—Formed Leads
X: Bare Die

Notice

Vitesse Semiconductor Corporation (“Vitesse”) provides this document for informational purposes only. This document contains pre-production
information about Vitesse products in their con ce pt , development and/or testing p hase . All i nformation in this document, including descriptions of
features, functions, performan ce, technical specifications and availability, is subject to change wi th out notice at any ti me. Nothing contained in this
document shall be c ons trued as e xten ding an y w arran ty or pr omise , e xp ress or imp lied , th at a ny Vitesse produ ct wi ll b e av ail able as described or
will be suitable for or will accomp lis h any particular task.

Vitesse products are not intended for use in life support applia nc es, devices or systems. Use of a Vitesse product in such applications without writ­ten consent is prohibited.

G52203-0, Rev 3.0 Page 13
05/11/01

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

VITESSE

SEMICONDUCTOR CORPORATION

Preliminary Data Sheet

SONET/SDH 2.5Gb/s Laser Diode Driver

VSC7923

Page 14 G52203-0, Rev 3.0

© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012

Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]

Internet: www.vitesse.com

05/11/01